A year after Chargers legend Junior Seau's death, more information continues to come out about concussions, CTE and their effect on sports, especially football

Former Chargers backup quarterback Wayne Clark has been experiencing memory problems that could be associated with brain injuries caused from playing in the NFL. Sports physicians talked about concussions and other brain injuries Thursday at the American Medical Society for Sports Medicine conference in San Diego.
— John Gastaldo/U-T San Diego/Zuma Press

Former Chargers backup quarterback Wayne Clark has been experiencing memory problems that could be associated with brain injuries caused from playing in the NFL. Sports physicians talked about concussions and other brain injuries Thursday at the American Medical Society for Sports Medicine conference in San Diego.
/ John Gastaldo/U-T San Diego/Zuma Press

Bailes’ Brain Injury Research Institute came up with $100,000 to fund Small’s study, and Bailes found a list of 20 subjects in California who were willing to participate.

Wayne Clark’s name was on that list, which shrunk to five after an initial evaluation deemed most of the participants unsuitable for the study.

The five former NFL players who eventually participated ranged in age from 45 to 73, and had played different positions – defensive line, linebacker, center, guard and quarterback. They’d all suffered from one or more concussions during their time in the NFL, and some were experiencing cognitive or mood symptoms.

The subjects were only told that they were participating in a study of the brain.

The first round of tests they went through were designed to gauge degree of depression and cognitive ability.

Then, they were injected with the FDDNP and put through the PET scan. All five were found to have markers of CTE in their brains.

Questions remain

Clark was told that his scans showed evidence of tau protein in his brain. However, unlike the other players who’d been tested, he showed no clinical symptoms of CTE.

He’d done well on the cognitive tests, and exhibited only signs of normal aging, with none of the mood disorders that the other players were suffering from.

Still, no doctor can definitively answer the question of whether the presence of tau in Clark’s brain could in time lead to the development of CTE.

“We know that NFL players have a fourfold greater risk of dying from Alzheimers,” Small said. “Wayne, even though he doesn’t have the symptoms now, he could develop Alzheimers.”

For the scientists, the discovery of tau in Clark’s brain opens more questions about CTE.

“When we see people like Wayne Clark who had just normal aging and tau in his brain on the scan, that tells us that it’s more than just the tau that’s causing the symptoms,” Small said. “There’s a lot of players who have multiple concussions who do fine. They become broadcasters later in life, they have no mental problems that we can notice.

“We think there may be genetic factors and other factors.”

The biggest knock against the UCLA study was the fact that only five people were tested. Critics say that sample size is too small and that more tests need to be conducted to determine whether the UCLA team has truly found a reliable way to test for CTE in the living.

The team doesn’t dispute that.

“They’re right. And we readily admit that. We qualified it and said, ‘It’s purely pilot data,’” said Bailes, Co-Director of the Chicago, Ill.-based NorthShore Neurological Institute.